This paper aims to integrate both economic and sociological notions of conventions in a single analytical definition. To this end, it starts by distinguishing conceptually between the prevailing notion of convention in economic theory, or behavioral convention, and the sociological notion of convention, or normative convention. The former is defined as an arbitrary, indeterminate, and stable social regularity, whereas the latter is defined as a principle of action prescribing how to behave in certain situations. After developing both concepts, they are integrated in a dual definition of social convention. The paper concludes presenting a typology of social conventions derived from the proposed definition.Este trabajo se ha beneficiado de la concesión de un Proyecto I+D financiado por el Ministerio de Educación y Ciencia y el FEDER, con referencia SEJ2006-00959/SOCI.